You may have the auto cast list generator enabled in the character element.
Go to Document > Page Layout > Options. If the box for Automatically Update Cast Element is checked, uncheck it. You'll have to manually retype the character names where this occurred, but any new character paragraph will be correct.
IMPORTANT: Live technical support (phone, chat, email) for Final Draft 8 has been discontinued. You will still be able to find information and solutions in this knowledge base and in the FD8 User Guide.
NOTE: All support for Final Draft 7, including software activation, has been discontinued. You may find solutions to problems in the online knowledge base or in the PDF manual found on the installation CD.